Vintage threads from the first ten years

Re: 56k from cw to ground helps some

Re: 56k from cw to ground helps someHi Rick, guys,
What am I missing here.....? Adding the 56K won't allow the signal to be pulled all the way to ground, and thus wouldn't give as deep a "trough".
If for example you took it to the extreme and stuck a 1M resistor in there instead of a 56K, there wouldn't be any modulation......right?

quote:"What am I missing here.....? Adding the 56K won't allow the signal to be pulled all the way to ground, and thus wouldn't give as deep a "trough"."

You really need to look at the schematic with this one. The pot shunts the LDR. When the pot wiper is grounded the LDR is effectively grounded on both sides. Opening the pot all the way connects the LDR to to the junction of the .1uF cap and 220K resistor, but it is still sees the 50KRA pot in parallel. Adding a 47K resistor between the pot and ground will raise the signal level because of the reduced load on the previous stage and effectively increase trem. depth since there is a larger signal being pulled to ground by the LDR, but now you can't turn the pot to ground so you have lost some adjustment range. This will also increase bass response somewhat which may or may not be desirable. HTH